function main(){
    var initAccount = _C(exchange.GetAccount)
    while(true){
        var account = _C(exchange.GetAccount)
        var dealAmount = account.Stocks - initAccount.Stocks
        var ticker = _C(exchange.GetTicker)
        if(BUYAMOUNT - dealAmount > BUYSIZE){
            var id = exchange.Buy(ticker.Sell, BUYSIZE)
            Sleep(INTERVAL*1000)
            if(id){
                exchange.CancelOrder(id) // May cause error log when the order is completed, which is all right.